<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        window.onload=function(){
            function clock(){
                //1.获取画布

                var canvas=document.getElementById("canvas");

                //2.获取画笔
                    var cx=canvas.getContext("2d");

                //3.设置画笔样式
                    cx.fillStyle='green';
                
                //4.绘制图形
                //绘制表盘
                    cx.beginPath();
                    cx.arc(250,250,200,0,Math.PI*2);
                    cx.closePath();
                    cx.fill();

                //绘制时刻度
                    cx.lineWidth=2;
                    cx.strokeStyle='black';
                    for(var i=0;i<12;i++){
                        cx.save();
                        cx.translate(250,250);
                        cx.rotate(i*Math.PI/6);
                        cx.beginPath()
                        cx.moveTo(0,-180);
                        cx.lineTo(0,-200);
                        
                        cx.closePath();
                        cx.stroke();
                        // cx.restore();

                        cx.font='16px blod';
                        cx.fillStyle='black';
                        // cx.save();
                        // cx.translate(250,250);
                        // cx.rotate(i*Math.PI/6);
                        cx.rotate(Math.PI/6);

                        cx.fillText(i+1,-5,-220);
                        cx.restore();
                    }
                //绘制分刻度
                    for(var i=0;i<60;i++){
                        cx.save();
                        cx.translate(250,250);
                        cx.rotate(i*Math.PI/30);
                        cx.beginPath()
                        cx.moveTo(0,-190);
                        cx.lineTo(0,-200);
                        cx.stroke();
                        cx.closePath();
                        
                        cx.restore();
                    }
                //绘制时针
                    var today=new Date();
                    var hour=today.getHours();
                    var min=today.getMinutes();
                    var sec=today.getSeconds();
                    hour=hour+min/60;

                    cx.lineWidth=5;
                    cx.save();
                    cx.translate(250,250);
                    cx.rotate(hour*Math.PI/6);
                    cx.beginPath()
                    cx.moveTo(0,8);
                    cx.lineTo(0,-110);
                    cx.closePath();
                    cx.stroke();
                    cx.restore();

                //绘制分针
                    cx.lineWidth=3;
                    cx.save();
                    cx.translate(250,250);
                    cx.rotate(min*Math.PI/30);
                    cx.beginPath()
                    cx.moveTo(0,8);
                    cx.lineTo(0,-150);
                    cx.closePath();
                    cx.stroke();
                    cx.restore();   

                //绘制秒针
                    cx.lineWidth=1;
                    cx.strokeStyle="red";
                    cx.save();
                    cx.translate(250,250);
                    cx.rotate(sec*Math.PI/30);
                    cx.beginPath()
                    cx.moveTo(0,10);
                    cx.lineTo(0,-180);
                    cx.closePath();
                    cx.stroke();
                    cx.restore();
                
                //绘制交界处
                    cx.save();
                    cx.fillStyle='#ccc';
                    cx.strokeStyle='#red';
                    cx.translate(250,250);
                    cx.beginPath();
                    cx.arc(0,0,5,0,Math.PI*2)
                    cx.closePath();
                    cx.fill();
                    cx.stroke();
                    cx.restore();   
                    setTimeout(clock,1000);
                }
            clock();
        }
    </script>
</head>
<body>
    <canvas id="canvas" width="600px" height="600px" style="background-color: #ccc;"></canvas>
</body>
</html>